Telephone system



o. ANDERS TELEPHONE SYSTEIA Original Filed Feb. 27, 1928 PLS Ffm- TI' Finders Patented Oct. 13, 1931 UNITED STATES PATENT OFFICE OTTO ANDERS, BERLIN-SCHMARGIENDORF, GERMANY, ASSIGNOR TO 'SIEMENS & HALSKE AKTIENGESELLSCHAFT, OF WERNERWERK, SIEMENSSTADT BEI BERLIN,

GERMANY TELEPHONE SYSTEM Applicatiouled February 27, 1928, Seriai No. 257,202, andmin Germany August 15, 1927. Renewed April 7, 1930.

The invention relates to an arrangement in telephone systems wherein several subscribers are allotted to one line as is the case in rural party lines, for example. vThe invention aims at facilitating the traffic bletween the subscribers connectcdto a party line Without influencing the connecting devices in the exchange and at permitting'establishment of connections to the exchange on the part of a subscriber on the party line. This is achieved in a particularly simple manner by the ringing of the exchange onl the part of a telephone station on the party line only taking place when vthe ringing operation is of a particular duration.

The connection of the party line to the exchange is preferably effected indirectly through repeater. This repeater is so formed that the bridge at the side of the party line is normally open in order to prevent disturbing influences during mutual calls of the subscribers on the party line, due to damping. The selection of a subscriber, not associated with the party line, e. g., a subscriber in the main exchange, is accomplished by the calling party line in such a manner as to actuatc a time switching device which closes the bridge in the repeater. The mutual calling of the subscribers is brought about in the usual manner by Morse signals in the magneto.

The drawing shows by way of example a rural party line R. P. L. connected to an automatic telephone exchange M. E. over the usual lineswitch L. S. of which only the wipers 13, 14and 15 are shown. In accordance with a common practice of schematic representation, the contacts operated by relays have been shown in the circuit separated from their relays and placed conveniently with relation to apparatus in which they perform some function. The relays are designated by capitalized reference characters, while their contacts are designated by corresponding small characters and numerals. An ordinary relay is represented by zig zag lines with a heavy line therethrough; a slow acting relay is shown in a rectangular cage; and a non-inductive resistance is indicated by ordinary zig zag llnes. The mode of the thermo-electric relay T71. is accomplished over the contact 1a of relay A, so th at nowif relay A has been operated for theV proper period of time, the V2' relay responds from ground, tf1., V2, to battery. Relay V2 operates its contacts 1/02 and 2v2 and .con-- nects thereby the impulse relay A1, which energizes over: ground, impulse contact 7 switchhook contact 8, choke coil 6, resistance 5, conductors 10 and 11, contacts 1r and 2r, left hand windings of repeater 12, contacts 102 and 2v2, winding of relay A1, to batt'ery. After the retraction of the A. C. relay A, the relay V2 consequently lies in the circuit from ground, lal, V2, battery. The sending of impulses commences now, and, upon the first retraction of Al, relay V1 -will respond from ground, 40, 3?;2, -V1, re-

sistance 20, to battery. The relay V1 having been previously short circuited over the contact 2a1.. Thus, the line conductors 16 and 17 are connected interruptedly to ground over 1/01, 2211 and 3a1. The lineswitch LS was operated in the usual manner immediately upon the energization of impulse relay A1, and consequent closure of its contacts 3a1, and rotated its wipers 13, 14 and 15 into engagement with the trunk conductors 16,l 17 and 18. The impulses transmitted by the calling station PLS by means of a well known calling device, of which only the impulse contact 7 is shown, effects a selector switch in the main exchange in a manner familiar to anyone versed in telephony. No detail account of this operation is therefore given in this application.

After the termination of the usual selector setting, the relay V1 will retract so that a speaking connection between the subscriber of the rural party line and a subscriber of the ad Learner automatic exchange is established. rEhe release will take place in known manner.

llt a connection is to be established in reverse direction, then the rural party line is reached over a selector in the main exchange seizingthe trunk line comprising conductors 19', 20 and 2l. ln this case, by energizing the C relay, the lineswitch of the party line is blocked and at the saine time the energization ot the relay U occurs from ground, lc, le, TU, to battery. Due to the closure of contact 1u, the relay V is energized over 20, 37', 1u, V, to battery, so that afterwards the relay Rllll responds from ground 3c, 3o, ltllll resistance 2l, to battery. Since the relays Rill( and lU are operated, no automatic ringing occurs (contacts 2u and 3u are opened, contacts lr and 51- are closed). By energizing the Rl winding over the contact Gc and conductors 20' and 21" in the selector, the relay R will retract due to the differential action of the two windings. rll`lhe relay U also retracts due to the openingz` ot contacts lo, and the Ril winding is intermittently interrupted during the actuation of the dial at the calling main exchange for the purpose of sending out ringing impulses., so that the Rlill winding comes into action and applies the ringing current to the rural line over the contacts 4r and 5r. At the end 'of the ringing current impulses, the speaking circuit is closed through contacts lr, 2r, and 50. 'll'he release of the connection is accomplished in known manner.

llt the party line is connected to a manually 'operated telephone system, the switching on ot the line signal atter the actuation of the time switching device is accomplished' by means of an auxiliary relay.

"What is claimed is:

l. lln a telephone system, a party line, an automatic exchange, a line provided for extending calls from said party line to said exchange, a time switching device at said exchange, meansior transmitting ringing current of particular duration over said call extending line, and means responsive to said ringing current :tor actuating said time switching device to effect a connection between said party line and said exchange.

2. ln a telephone system, a party line, an automatic exchange, a line provided for extending calls from said party line to said exchange, a thermo-electric time switching device at said exchange, means at a calling party line station for transmitting ringing current oversaid call extending line, means at said exchange responsive to said ringing current, and means actuated thereby `-for operating said time switching device only it said ringing current is of a particular duration to effect a connection between said party line and said exchange.

3. ln atelephone system, a party line, an automatic exchange, a line provided 'for extending calls from said party line to said exchange, an alternating current relay connected to said call extending line, means at a calling party line station to transmit ringing current over said call extending line to operate said alternating current-relay, a thermoelectric time switching device, and means actuated by said relay for operating said time switching device to eil'ect a connection between said calling party line and said cxchange only if that ringing current is of particular duration.

et. lln a telephone system, a party line, an automatic exchange, a line to said exchange for extending calls :trom a calling party line to a called line in said exchange, a repeater and an automatic switch associated with said call extending line and normally disconnected therefrom, a time switching device in said exchange, means for transmitting ringing current of a particular duration over said call extending line, means responsive to said ringing current for actuating said time switching device, and means operated by said time switching device toconnect said repeater to said call extending line and to close a starting circuit for said automatic switch to effect a connection between said calling party line and said called line in the exchange.

5. lin a telephone system, a party line, an automatic exchange, a repeater comprising two inductively connected sections, one ot said sections being normally open, a line terminating in said open section of said repeater and provided for extending calls from a calling party line to a called line in said ex- 19C change, an automatic switch connected to said other section of said repeater, a time switching device, means at a calling party line station tor transmitting ringing current over said terminating line, means responsive l to said ringing current for actuating said time switching device, and means operated by said time switching device after the lapse ot a certain period depending on the continuous application of said ringing current, :tor 110 closing the normally open section of said repeater and tor closing a starting circuit for said automatic switch to effect a connection between said calling party line and said exchange. y

6. ln a telephone system, a party line, an automatic exchange, a repeater comprising two inductively connected sections, one of said sections being'normally open and provided with an impulse receiving and repeat- 120 ing relay, a' line terminating in said open section of said repeater and provided for extending calls trom a calling party line to a called line in said exchange, an automatic switch connected to said other section of said 123 repeater, a time switching device, means at a calling party line station for transmitting ringing current over said terminating line,y means responsive to said ringing current for actuating said time switching device, and 129 means operated by said device after the lapse of a certain period depending upon the continuous application of said ringing current, 'f or closing the normally open section of said repeate` and for connecting'said impulse relay to said terminating line, and for closing a starting circuit for said automatic switch to ell'eet a connection between said calling line and said automatic exchange.

7. In a telephone system, a substation, an automatic exchange, a line for extending calls between the two, means at the substation for transmitting ringing current over said line, and means at the exchange responsive to ringing current of a particular duration over said line for effecting a connection between said substation and said exchange.

S. In a telephone system, an automatic exchange, a line terminating in said exchange, a substation on said line, means at said substation for transmitting ringing current over said line to said exchange, a relay in said exchange operated by said ringing current and maintained operated thereby throughout the duration thereof, and means controlled by said relay and effective after said relay has been maintained operated for a certain period to connect said substation to said exchange.

9. In a control system, one station, another station` remotely disposed therefrom, a source of direct current at said one station, an

`alternating current source at said other station, a line interconnecting said stations, and means in said one station responsive to a flow of alternating current over said line from the current source at the remote station for setting up a direct current flow over said line from the current source at said one station.

10. In a control system, one station, another station remotely disposed therefrom, a source of direct current at said'one station, a current source at said other station, a line interconnecting the two stations, apparatus at the said one station, means in said one station responsive to a current flow over said line from said remote station source for setting up a direct current low over said line from said one station source, and means at said remote station for thereafter controlling the current flow from said one station source to operate said apparatus.

11. In a telephone system, a substation, an automatic exchange, a line extending between the two, automatic switches for extending a call to substation in the exchange, a current source at the substation, a direct current source in the exchange, means in the exchange responsive to a current flow over said line Afrom said substation source for setting up a direct current flow over said line from said exchange source, and means at the substation for thereafter controlling the current How from said exchange source to operate said and a called line, a current source at said substation, a current source in said exchange, means in the exchange responsive to a current flow over said calling line from said substation source for establishing a current flow over said calling line from said exchange source, and means at the substation forproducing interruptions in the current flow from said exchange source for controlling said automatic apparatus to establish a connection between said calling line and a called line.

13. In a telephone system, a calling line', a substation on said line, an exchange having automatic apparatus for establishing av telephonie connection between said calling line and a called line, a current source at said substation, a current source in said exchange, timing means in the exchange responsive to a current flow of a, particular duration over said calling line from said substation source for establishing a current flow over said calling line from said exchange source, and means at the substation for producing interruptions in the current flow from said exchange source -for controlling said automatic apparatus to establish a connection between said calling line and a called line.

14. In a telephone system, a' calling line, a substation on said line, a telephone exchange, a source of alternating current at the substation, a source of direct current at the exchange, and means in the exchange responsive to a flow of alternating current over said line for establishing a connection between said substation and said exchange and for setting up a iow of direct current over said line,

15. In a telephone system, a party line, an exchange, means for transmitting ringing current over said line to said exchange, and means in said exchange responsive to the flow of ringing current of a particular duration only for effecting a connection between said line and saidl exchange.

16. In a telephone system, a line having a substation provided with a source of current, an exchange, and means in said exchange responsive to a flow of current of a particular duration only over said line from said source for effecting a connection between said line and said exchange.

17. In a telephone system, an exchange, a calling line terminating in said exchange, a plurality of substations on said line, each substation having means for generating current to signal other substations on the line, and an automatic switch in said exchange responsive to current of a definite duration only from one of seid suhstutions for extending the ceiling line therein.

18. in a telephone systern9 en exchange, e line terminating in seni exchange, e, piumiity of substations on the tine, each substation having u hand generator whereby the other stations on the line can he signalled endl an automatic switch in the exchange responsive to the continued operation ot any one ont said hand generators for u denite minimum period for extending seid line therein..

in witness whereof, it hereunto subscribe my name this 26th dey oi Junuury9 L D,

@TTG ANDERS.

s neer/eer 

